As it has been reported that almost 80% of the information a human receives from the outside world is visual information, eyes are one of the most important sensory organs for human. Thus, although most of eye diseases may not be lethal, an eye disease which may eventually lead to loss of vision can significantly impair everyday life of a human so that a development of a therapeutic method for treating such disease is very important for human beings.
As one of the most important eye diseases that may eventually lead to loss of vision, a disease accompanied with retinal degeneration or optic nerve degeneration, which lead to loss of vision due to retinal nerve damage, can be mentioned. Such degeneration induces symptoms such as reduced visual acuity, narrowed vision field, damaged vision field, ocular circulation impairment, etc. and can eventually lead to loss of vision.
In particular, glaucoma, in which retina is impaired by elevated intraocular pressure, becomes a big problem with aging population. As such, for developing a therapy using a drug which is effective for treating an eye disease such as glaucoma, etc., establishing an animal for eye disease model which has ocular hypertension and/or retinal degeneration is a very important task to be achieved.
Until now, various types of model animals expressing symptoms of an eye disease have been prepared. Most of them are a model animal in which symptoms same as those found for an eye disease are induced by administration of a certain compound or a drug. For example, in Patent Document 1, a model animal having retinosis with damaged blood vessel of retina caused by administration of Rose-Bengal to a GK rat, i.e., an animal with congenital diabetes mellitus, is disclosed. Further, in Patent Document 2, a laboratory animal in which ocular hypertension and optic nerve damage are induced by injecting a solution containing a cross-linked polymer to an anterior chamber is disclosed. Meanwhile, according to Patent Document 3, GLAST knock-out mouse is disclosed as a model having glaucoma with normal intraocular pressure in which the function of endogenous GLAST gene is impaired, and it is one example of a model animal having symptoms of an eye disease that is caused by inhibiting a function of a certain gene.
However, for the former case which discloses a model animal having symptoms same as those found for an eye disease that are induced by administration of a certain compound or a drug, a problem has been pointed out that an issue associated with reproducibility or a question regarding whether or not a relationship between the symptoms induced and actual cause of a disease is directly reflected remain unsolved. In addition, for the latter case, the use of the GLAST knock-out mouse is limited to a model having glaucoma with normal intraocular pressure.
Patent Document 1: International Publication No. WO2004/080166 pamphlet
Patent Document 2: JP-A No. 2003-149236
Patent Document 3: International Publication No. WO2004/092371 pamphlet